Catalytic converters for the treatment of a gas stream are generally known, especially in connection with exhaust gas treatment for internal combustion engines of motor vehicles. They may contain a number of components, especially three-way catalytic converters, hydrocarbon adsorbers and a porous structure, which may be embodied especially as a mesh, as a screen or as a honeycomb body. Such systems are known, for example, from EP 0 638 710 A2 and EP 0 485 179 A2.
A special problem of such catalytic converters is that they shall function already in the cold start phase. To ensure this, it is known, for example, from DE 10 2007 024 563 A1 that catalytic converters can be equipped with an electrically heatable honeycomb body, which is used to heat the exhaust gas.
Heated porous structures known from the state of the art operate according to the principle that the heating effect is achieved through a flow of current through at least some of the wires, plates or plate stacks, which together form the porous structure. Since a uniform heating effect is desirable, it is necessary to apply current to a plurality of wires, plates or plate stacks and to ensure, on the one hand, that the current paths thus formed have a resistance that is defined as a fixed resistance that is especially identical to the extent possible and, on the other hand, to ensure an electrical insulation between the wires, plates or plate stacks. In particular, an electrically insulated suspension of the wires, plates or plate stacks is necessary for this. All these insulations hinder the flow of exhaust gas. As a result, all this leads to a complicated and expensive manufacturing process, which also leads, moreover, to a heatable catalytic converter that is sensitive to vibrations and has a considerable risk of failure.